Deidre Ademyne is Eskel's surprise child. She became Eskel's "Unexpected Child", as Vesemir puts it, when the witcher saved her father's, then the prince of Caingorn, life. In gratitude, the prince promised Eskel "that which he would find but did not expect" when he returned home. This, as it turned out was the pregnancy of his wife, and therefore Deidre. Because of this Eskel and the girl share a special bond. For example, Deidre says that she need only think of Eskel to know exactly where he is at any given time. She says they are bound by Destiny.

Deidre is first in line to inherit the titles of her recently deceased father. It appears the elder Ademeyn succumbed to syphilis. The second in line, her brother, Merwin Ademeyn, a nobleman on King Henselt's council, does not want her to rule as he believes she is not fit. He seems quite willing to make sure she will not have the crown, enlisting the help of a powerful sorceress.

Deidre was born during an eclipse, and this is why she is considered to be affected by the so-called Curse of the Black Sun. She appears completely normal, but she does emit an aura which has apparently been increasing in power over the years. This aura prevents magic from being used in her presence, and this includes witchers' signs as well as spells cast by other magic users. Deidre herself says that her aura also dispels previously cast spells when she is present.

From Merwin, we hear a sad tale from Deidre's childhood. It seems that at the age of 12 she was raped by a charlatan claiming to be a mage. Actually, he claimed to be an altogether different kind of specialist: an oneiromancer, or diviner of dreams. This "mage" claimed that he needed to spend a night in Deidre's chamber as she slept. He would mix a brew designed to amplify her dreams. The old man could barely walk, had a beard down to his waist... Deidre's family suspected nothing.

He seemed to do as he claimed he would. By morning he was gone, but several valuable items had also disappeared from Deidre's chamber, including her favourite mother of pearl comb... Only the laundresses in the outskirts saw the miscreant, claiming that he fled as if chased by demons.

The prince ordered a search, but it was too late. Her father, who had hired the mage, refused to believe her claims of rape, saying that the cheat was an old man... And the bed linens betrayed nothing... This caused Deidre to flee assisted by "a young stable boy described as "an excessively broad-shouldered oaf". This could have been Roben, a man later described as a lover of both Deidre and Sabrina Glevissig, depending on whom you believe.

A search party was organized to find the youngsters, but they had disappeared without a trace. A week later, folk inhabiting the area where he was found claimed to have seen a young girl and boy ride through on large wolves... the stuff of fairy tales. The charlatan was ultimately found dead, having had his "manhood" removed. The implication being, of course that Deidre extracted her revenge most violently.

After some time passed, Deidre returned to the castle. From then on her father ordered the dogs set upon any mages that approached, assuming that any true sorcerer would surely manage to avoid a few bear-hunting hounds... And then Sabrina appeared.

Deidre can be found inside the walls of Kaer Morhen where the witchers have taken her in. She camps in the inner courtyard, accompanied by her faithful companions, Beann'shie and D'yaebl.

Merwin Ademeyn admits that as the first-born child, Deidre is legally entitled to inherit all titles and estates from their father. However, he simultaneously claims that she has lost that right and certainly should not rule given that she is a cruel changeling.

According to the sorceress Sabrina Glevissig, Deidre Ademeyne has been affected by the Curse of the Black Sun, rendering her a mutant both cruel and evil.

Deidre became Eskel's Unexpected Child when the witcher saved her father's life. In gratitude, the prince of Caingorn promised Eskel whatever unexpected thing he found when he returned home. Eskel and the girl share a special bond, some might even say they are bound by Destiny.

Deidre has a special affinity with wolves and dogs, stories of her are littered with references to them. She wears a silver brooch with the profile of a wolf's head on it, and she is always accompanied by two black wolves, Beann'shie and D'yaebl.

Deidre is very similar to Renfri from the short story "The Lesser Evil", the similarities going even as far as Deidre quoting, word for word, the latter.

As a name, Deidre is another form for Deirdre, a noble beauty destined for tragedy since her birth in Irish legends.